Recent taxonomic studies have confirmed that the subfamily emydinae is a natural group and includes the Spotted Turtle and its closest relatives in the traditional genera Clemmys, Emys, Emydoidea, and Terrapene (Bickham et al., 1996; Burke et. al, 1996; Feldman and Parham, 2001). However, recent revisions reveal that the traditional genus Clemmys was paraphyletic, and recommended placing the Wood Turtle ("Clemmys" insculpta) and the Bog Turtle ("Clemmys" muhlenbergii) together into the genus Glyptemys, leaving the Spotted Turtle as the sole remaining member of the genus Clemmys (Holman and Fritz, 2001; Feldman and Parham, 2002).
Ernst (1983) reported a hybrid between the Spotted Turtle and the Bog Turtle, Glyptemys (=Clemmys) muhlenbergii. These species are similar in size and overlap in habitat requirements.
Clemmys guttata is a very small species that rarely exceeds a straight-line carapace length of 11.4 cm (4.5 inches); the maximum recorded carapace length is 13.6 cm (5.4 inches). The adult carapace is smooth, without obvious growth ridges (annuli), and is black or brownish-black with a variable number of round yellow spots. These spots may fade in old adults, and occasional specimens lack carapace spots altogether. The plastron is yellow or orange with a black blotch covering a portion of each scute; in some male or old female specimens the black pigment can cover nearly the entire plastron. Growth rings (annuli) are usually visible on plastral scutes; counting these annuli is an unreliable method for determining the age of a mature specimen, though such a count may allow an estimate of a specimen's minimum age.
The head is mostly black, with a variable number of yellow spots; there is usually a large, sometimes divided, yellow or orange blotch on each side of the head. The upper jaw is notched medially. The upper surfaces of the legs and tail are black, again usually with a scattering of yellow spots, and the lower surfaces of the legs and neck are orange to pink or salmon-red.
The sexes are dimorphic, and easily distinguished in mature specimens. Males have a more elongate and compressed carapace, and a concave (centrally depressed) plastron. The male's eyes are typically brown, and the chin is tan, brown, or black. The male's tail is comparatively longer and thicker, with the vent (anal opening) beyond the edge of the carapace with tail extended. The female has a higher, more rounded carapace, and a flat plastron. The female's eyes are usually orange and her chin is yellow or orange. The female's tail is comparatively narrow, and when extended, the vent is at or beneath the edge of the carapace. Females are slightly larger than males, on average.
The hatchling Spotted Turtle has a nearly circular carapace from 2.5 to 3.1 cm in length; coloration above is like the adult but with only one spot per scute. The tail may be nearly as long as the carapace. Juvenile Spotted Turtles have more conspicuous scute annuli on their carapaces than do the adults (Ernst, Lovich, and Barbour, 1994; Harding, 1997).
Other Physical Features: ectothermic ; bilateral symmetry
Average lifespan
Status: captivity: 6.1 years.
Average lifespan
Status: captivity: 26.0 years.
Average lifespan
Sex: male
Status: captivity: 8.3 years.
Spotted Turtles prefer shallow waters with a soft bottom substrate and some submergent and emergent vegetation. These can include sedge meadows, boggy ponds, fens, tamarack swamps, sphagnum seepages, and slow, muddy streams. These turtles also frequently wander on land between wetlands, and (as noted above) may aestivate on land for weeks at a time (Ernst, Lovich, and Barbour, 1994; Harding, 1997).
Terrestrial Biomes: forest
The range of Clemmys guttata is roughly divided into two possibly discontinuous portions of eastern North America; the first extends along the eastern seaboard from southern Maine through New England and south through the eastern (largely coastal plain) portions of Virginia, the Carolinas, Georgia, and northern Florida. There are isolated populations recorded in southeastern Quebec and adjacent northern Vermont, and in the western Carolinas. The second (Great Lakes) portion of the range extends from northeastern Illinois into the western and southern Lower Peninsula of Michigan, northern Indiana, Ohio and western Pennsylvania, and across extreme southern Ontario into western New York. Isolated populations occur in central Indiana and the Georgian Bay region of Ontario (Barnwell et al., 1997; Bartlett and Bartlett, 1999; Conant and Collins, 1998; Ernst, Lovich, and Barbour, 1994; Harding, 1997).
Within this range, the Spotted Turtle is spottily distributed in the remaining suitable habitat, and most populations are small and colonial in nature. Generalized population declines and local extirpations have occurred, especially in the Great Lakes portion of the range, but more recently in the East as well (Klemens, 1993; Ernst, Lovich, and Barbour, 1994; Harding, 1997).
Biogeographic Regions: nearctic (Native )
Spotted Turtles eat a variety of plant and animal foods, which are consumed in the water. Feeding does not begin in spring until water temperatures reach about 15°C (Ernst, 1982). Vegetable foods include algae, leaves of soft aquatic plants, and water lily seeds. Animal foods include worms, mollusks, crustaceans, adult and larval insects, amphibian eggs and larvae, and carrion (Behler, 1996; Ernst, Lovich, and Barbour, 1994; Harding, 1997).
Clemmys guttata occupies a rather specialized ecological niche in habitats that are comparatively rare and biologically diverse. This small, brightly colored turtle is aesthetically appealing to humans, which unfortunately has resulted in a high demand for them in the commercial pet trade (see "Conservation" below).
This turtle is harmless to human interests.
The specialized wetland habitats used by Spotted Turtles have been widely drained and converted by humans into agricultural and residential land, or modified into more open aquatic habitats not favored Spotted Turtles. Many of the remaining Spotted turtle populations are now very small and isolated, with little or no opportunities for genetic exchange with other sites (this is especially the case in the Great Lakes area, but is true in other parts of the range as well). As these turtle "colonies" become increasingly isolated, they also become more vulnerable to human exploitation and to predation by "subsidized" predators such as raccoons (Harding, 1997, and pers. ob.).
Like its close relatives, the Wood Turtle (Clemmys insculpta) and Blanding's Turtle (Emydoidea blandingii), the Spotted Turtle exhibits certain life history traits that cause it be be unusually vulnerable to human exploitation and habitat degradation. These traits include: high egg (and probably hatchling) mortality, low reproductive potential under natural conditions, and delayed sexual maturity (7 -- 14 yrs), balanced by relatively long potential adult breeding life. Species with these traits will predictably require high annual survivorship of mature adults and older juveniles to maintain population stability. Any factor which reduces adult survivorship below expected natural levels (such as collecting or harvest by humans, road mortality, or an increase in predator numbers) will inevitably lead to a declining population, and perhaps eventual extinction of the population. It is thus reasonable to manage Spotted Turtles (and other long-lived turtle species) with the assumption that they have no harvestable surplus in their populations (Congdon et al., 1993, 1994; Harding, 1997). Most states and provinces do offer this species some degree of legal protection from exploitation, but protection is not yet consistent or universal over the turtle's range (Levell, 1997). Spotted turtles are listed as vulnerable on the IUCN's Red List, and they are considered threatened in the state of Michigan.
US Federal List: no special status
CITES: no special status
State of Michigan List: threatened
IUCN Red List of Threatened Species: vulnerable
Spotted Turtles probably reach sexual maturity at an age of 7 to 14 years, at a carapace length of about 9 cm (3.5 inches), with northern animals probably taking longer to mature than those living farther south (Ernst, 1970; Harding, 1997).
Courtship and mating activity begins soon after emergence from winter dormancy; in Pennsylvania, Ernst (1982) recorded Spotted Turtle courtship at a water temperature of 8.5°C, while Ontario turtles were courting at a temperature of 2°C (Litzgus and Brooks, 2000). Male Spotted Turtles may fight each other, presumably over access to females. Courtship involves the male chasing the female under water while nipping and biting her legs and carapace; he then mounts her shell and bites at her head and neck. Copulation occurs in shallow water and may last for an hour (Ernst, Lovich, and Barbour, 1994; Harding, 1997).
Nesting can occur from late May through June. Females typically lay only one clutch of from 1 to 8 eggs per year, though a few may lay a second, smaller clutch a few days after the first. Captive females have been reported to lay multiple clutches and far more eggs in a year's time. One captive female from New York produced eight clutches in a thirteen month period, for a total of 42 eggs (J. Czech, pers. comm.). Such reports suggest that female Spotted Turtles are capable of a greater production of eggs than is normally seen in the wild, but are constrained by unknown environmental factors (such as a limited food supply or short activity season).
Nesting females seek open, sunny locations that offer moist, but well-drained, soils. If better sites are lacking, nests may also be placed in the tops of sedge hummocks or in accumulations of vegetation (such as decaying leaf litter). The nests are dug with the hind feet. The eggs, 2.5 to 3.4 cm long, are elliptical and have thin, flexible shells. Incubation requires from 44 to 83 days, with faster development at higher temperatures. Most young emerge from their nests in August or September, but overwintering in the nest has been reported (Ernst, Lovich, and Barbour, 1994; Harding, 1997).
The sex of the hatchlings is determined by nest temperature during the middle third of the incubation period; in the lab, cooler experimental temperatures ( 22.5° to 27°C) produced mostly males, and warmer temperatures (30°C) produced only females (Ewert and Nelson, 1991).
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate)
Average gestation period: 77 days.
Average number of offspring: 3.
Average age at sexual or reproductive maturity (male)
Sex: male: 2920 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 2920 days.
The spotted turtle (Clemmys guttata), the only species of the genus Clemmys, is a small, semi-aquatic turtle that reaches a carapace length of 8–12 cm (3.1–4.7 in)[4] upon adulthood. Their broad, smooth, low dark-colored upper shell, or carapace, ranges in its exact colour from black to a bluish black with a number of tiny yellow round spots. The spotting patterning extends from the head, to the neck and out onto the limbs. Sexually mature males have a concave plastron and a long, thick tail. By contrast, sexually mature females possess a flat plastron and have a tail that is noticeably shorter and thinner than that of mature males. Mature males also have a dark iris and face; females typically have a yellow or orange iris and a similarly coloured face that is distinctly lighter than the males'. Juveniles appear female-like in this regard, and at maturity males begin to develop darker features.
Spotted turtles are aquatic omnivores that inhabit a variety of semi-aquatic or in other words, shallow, fresh-water areas such as flooded forests, marshes, wet meadows, bogs and woodland streams in southern Canada (Ontario) and the eastern US: the eastern Great Lakes and east of the Appalachian Mountains.[5]
The spotted turtle is the only species in the genus Clemmys, which was first named in 1828 by Ferdinand August Maria Franz von Ritgen.[3][6] Johann Gottlob Schneider originally described the species as Testudo guttatai in 1792; however, he is now the authority for the current binomial name, Clemmys guttata.[6] Until recently, the genus Clemmys consisted of four species (bog turtle, spotted turtle, western pond turtle, and the wood turtle). Recent genetic analyses have revealed that the spotted turtle is distinct from the other three species.[7] The bog turtle and the wood turtle were moved to the genus Glyptemys, while the western pond turtle has been renamed Actinemys, leaving the spotted turtle the only member of its genus.[8]
The spotted turtle is small and has a gray to black base color.[9] Its upper shell (carapace) is smooth, does not have a central ridge running down the middle (called a "keel"),[10] and grows to 3.5–12.5 cm (1.4–4.9 in) in length.[11] It is also totally black and contains anywhere from zero to about one hundred yellow spots, which are a defining characteristic of this turtle.[11] Although perhaps inconsequential, it has been found that the left side of the upper shell has more spots than the right.[9] Spots can always be found on the head, neck, and limbs.[12] The bottom shell (plastron) is yellow or orange-yellow and a black spot is present on each section (scute); however, with age, melanism of the plastron increases until the entire surface is black.[10]
The head is black and the upper jaw is notched.[10] On each side of the head is a large orange blotch.[13] Also present are several yellow bands of varying size.[9] Skin on the dorsal side of the turtle is black with sparse yellow spots while skin on the ventral side may be brighter: orange, pink, or red. These lightly pigmented areas do vary geographically [10] and the tail of some individuals has yellow striping.[13] Regarding the geographical variation in spots, southern individuals tend to have smaller and less conspicuous spots than those of individuals from farther north.[9] The spotted turtle's karyotype consists of 50 chromosomes.[10]
Visual differences between male and female turtles develop around the time of sexual maturity. The male spotted turtle has a tan chin, brown eyes, and a long, thick tail. The chin of the female is yellow; she also has orange eyes and a shorter tail than the male. In addition, the bottom shell of males is concave while it is either flat or convex in females. On average, females grow to be slightly larger than males.[10] Also, females have more spots than males (on average).[9]
Hatchlings resemble the adults closely. Consistently, each segment of the upper shell has only one yellow spot.[14]
The spotted turtle ranges from southern Maine, Quebec, and Ontario, south along the eastern US to Florida in the east and central Indiana and Ohio in the west.[10][11] Disjunct populations exist in the Canadian portion of its range and also in central Illinois, central Georgia,[11][15] North Carolina, South Carolina, and Indiana.[16] In Indiana and Illinois, the species is found only in the northern portion of the state but it is found on most of the lower peninsula of Michigan. The highly fragmented distribution of spotted turtles in Ohio only covers the northern two-thirds of the state.[16]
The spotted turtle occupies a variety of habitats including swamps, bogs, fens, marshes, woodland streams, and wet pastures. Also, brackish streams that are influenced by tides can also serve as a home to this turtle[17] in addition to ditches, vernal pools, and sedge meadows.[13] For a habitat to be sufficient for spotted turtle survival it must have areas of soft substrate and at least some aquatic vegetation.[17] An optimum habitat would include shallow and slow-moving waters with soft muddy soil, sedge tussocks, water lilies, sphagnum moss, and cattails.[13] Because it is so often found in areas that contain duckweed, the yellow spots on these turtles may serve as a form of camouflage.[15] The spotted turtle avoids artificial reservoirs and deep, open-water areas.[15]
The spotted turtle can be decidedly terrestrial, spending a good amount of time on land[17] and sometimes basking on patches of grass near its body of water.[18] The females during times of nesting will travel onto land and lay eggs on sunny soil. Nesting also may take place in other terrestrial locations, for instance near man-made dikes or the nest of a muskrat.[13]
A study in Pennsylvania analyzed the reproductive biology of the spotted turtle. Sexual maturity is not reached until age 8,[19] upon which researchers found that courtship and nesting periods typically ranged from March until June. The courtships involved females being frantically chased by one to several males for approximately 15 to 30 minutes. During the chase, females’ tails and legs were often bit by males. If two males were present, they occasionally stopped the chase to fight with one another and the losing male retreated. When the female was caught, the male mounted her and placed his tail beneath the female while grasping her carapace tightly. Females later constructed their nest in well-drained areas that were exposed to full sunlight. Clutches can range from 1–8 with an average of 3–4. These animals also exhibit temperature-dependent sex determination, meaning that the outside temperature during the incubation period determines the sex of the hatchling with males resulting from the temperature being lower and females when it's higher. After the eggs were laid, they were arranged in the nest by alternate movements of the hind feet. The hind feet were also used to scrape soil and grass back into the nest cavity. Incubation periods were estimated to range between 70 and 83 days.[20]
Although the spotted turtle has been observed in Quebec, no permanent population is known to exist there. However, 104 populations have been discovered in Ontario. Most of these concentrated around Georgian Bay, on the north shore of Lake Erie, and southeastern Ontario. Of the original 104 sites noted, 36 are known to no longer have spotted turtles.[13]
Despite the seemingly large number of populations in Canada, many are not self-sustaining because of the following reasons: the majority of the populations are small, they all have less than 200 individuals, and the areas are all isolated from one another. All told it is estimated that anywhere from 1000 to 2000 spotted turtles live in Canada however, with individual populations ceasing to exist, this number is declining.[13]
The spotted turtle's range overlaps that of many other turtles. It can often be found in the same wetlands as wood turtles, bog turtles, snapping turtles, painted turtles, Blanding's turtles, eastern box turtles, common musk turtles, and eastern mud turtles.[18]
The spotted turtle is one species whose sex is determined by temperature during embryonic development. Some researchers have claimed that global warming may deleteriously impact population sex ratios.[21]
During the freezing temperatures of winter and the extreme heat of summer, spotted turtles become inactive during environmentally unfavorable conditions. However, the species appears to be relatively tolerant of drought conditions. Spotted turtles do become active very early in the spring, and are often active at relatively cold water temperatures during that season. Activity appears to peak during April and May in the northern part of the range. In the warmest part of the summer (when water temperatures exceed 30 °C), they may aestivate terrestrially or aquatically for long periods of time. During summer dormancy, the turtles may burrow into leaf litter in woodlands or marsh edges or open fields; others remain in muskrat burrows or other aquatic refuges.[22] Litzgus and Brooks (2000) have questioned the common presumption that summer dormancy is an attempt by the turtles to avoid high temperatures; data from Ontario and elsewhere suggests that avoidance of predation and conservation of energy resources may be viable alternate explanations. No matter the explanation for dormancy, the "winter" dormant period may commence in late summer or fall, but in almost every instance after a return to aquatic habitats.[22][23]
Spotted turtles home ranges tend to occupy limited areas of about 0.5 to 3.5 hectares (1.2 to 8.6 acres).[22][23] Note that due to their size, these small turtles are highly vulnerable to predation, particularly during their frequent terrestrial wanderings. Many specimens will show mutilation injuries and scars from past predation attempts. Raccoons (Procyon lotor) are particularly adept at consuming and killing this species. Spotted turtles have been observed to dive into the water and bury themselves in the bottom mud when surprised while basking. Muskrats kill many spotted turtles during the winter dormant period.[22]
The spotted turtle is an active hunter: seeking out prey items in the water by pointing its head into aquatic plants.[24] It feeds at temperatures above 14.2 °C (57.6 °F), which in its range corresponds to roughly the middle of March onward until September. It is omnivorous and eats exclusively in the water,[24] consuming plant material including aquatic vegetation, green algae, and in at least one instance, wild cranberries. Animal food includes aquatic insect larvae,[25] worms, slugs, millipedes, spiders,[26] crustaceans, tadpoles, salamanders, and several genera of small fish. These items are consumed alive or dead but always in the water.[25] Some of the insects commonly found in with the spotted turtle's stomach contents are terrestrial, suggesting the turtle moves onto land to hunt.[26] In captivity, these turtles will eat fruits such as cantaloupe and watermelon and fresh and canned fish.[26]
The spots on spotted turtles vary greatly throughout their range. They can have up to a hundred spots, while some have no spots at all. Spotted turtles shed their scutes in small pieces occasionally resulting in completely smooth shelled specimens. These are very intelligent turtles and have been tested like the wood turtles in mazes and have been proven to have the brain capacity of a mouse. These turtles are only active in the cooler spring months. The spotted turtle is declining throughout eastern North America due to habitat loss and poaching. One study focused specifically on the Southeastern population, and recorded that females had greater shell heights, heavier body masses, and longer plastrons than males.[27] In another study, where radio-telemetry was used, spotted turtle behavior was observed in northeastern America, where distinct seasonal movement patterns revealed that spotted turtles exhibited a positive association in wetlands hosting abundant wood frog egg masses in spring and from spring to late summer, a negative association in forested wetlands was detected.[5] Spotted turtles require frequent terrestrial movements for their diverse habitat requirements which exposes them to potential threats including unsustainable sources of adult mortality such as road kill and illegal collection.[5] Recovery action is necessary to prevent decline of spotted turtles since this species has been determined to have a high risk of extinction in several areas ranging from South Carolina up to Maine in the US and even further north into Ontario, Canada, mitigation requires spatial and temporal shifts in habitat use.[5]
In Canada, the spotted turtle is federally endangered,[13] while in the United States the spotted turtle is currently under review by the United States Fish and Wildlife Service for protection under the Endangered Species Act.[28] It is listed by the IUCN as endangered,[1] and has "listed" status in many of the states where it occurs. For example, in Indiana the spotted turtle is listed as an endangered species.[29] In the Northeast, it has protective status in five of the six New England states and is listed as a species of special concern in New York.
Habitat destruction, alteration, and conversion, collection for the pet trade, and other human impacts such as vehicle mortality (cars and mowers) are leading to declines in populations.[25] Vehicular mortality is particularly impactful because turtles crossing roads are likely pregnant female turtles in search of a nesting site.[30] Additionally, since reproductive rates of these turtles are low, spotted turtles are extremely susceptible to population impacts.
Due to their aquatic habitat, these turtles are particularly sensitive to pollutants and toxic substances. They will disappear rapidly from areas with declining water quality.[30]
New Hampshire has identified some ways to conserve the habitat of spotted turtles.[31] These include:
The spotted turtle (Clemmys guttata), the only species of the genus Clemmys, is a small, semi-aquatic turtle that reaches a carapace length of 8–12 cm (3.1–4.7 in) upon adulthood. Their broad, smooth, low dark-colored upper shell, or carapace, ranges in its exact colour from black to a bluish black with a number of tiny yellow round spots. The spotting patterning extends from the head, to the neck and out onto the limbs. Sexually mature males have a concave plastron and a long, thick tail. By contrast, sexually mature females possess a flat plastron and have a tail that is noticeably shorter and thinner than that of mature males. Mature males also have a dark iris and face; females typically have a yellow or orange iris and a similarly coloured face that is distinctly lighter than the males'. Juveniles appear female-like in this regard, and at maturity males begin to develop darker features.
Spotted turtles are aquatic omnivores that inhabit a variety of semi-aquatic or in other words, shallow, fresh-water areas such as flooded forests, marshes, wet meadows, bogs and woodland streams in southern Canada (Ontario) and the eastern US: the eastern Great Lakes and east of the Appalachian Mountains.
